In a large bowl, stir
eggs, vanilla and sugar {do not beat}. Pour in warm chocolate butter mixture
and stir. Set aside to cool to room temperature, another 15 minutes or so.

Stir in flour, baking
powder & salt until combined. In a separate bowl, stir butterfinger bits
with mini chocolate chips and 1 tablespoon of flour. Pour into batter and stir.

Pour batter into prepared
pan and bake 15 minutes. Rap pan against the oven shelf to force the air to
escape from between the pan and the brownie dough. Bake for about 10 minutes,
until a toothpick comes out clean. Do not overbake! Allow to cool thoroughly,
refrigerate, and cut into squares.